• New formulation delivers drug levels that are predicted
to significantly increase utrophin production
• Summit to progress utrophin upregulator into next stages of
development

Oxford, UK, 7 November 2012 – Summit (AIM: SUMM), a UK drug
discovery company, announces that the repeat dosing of the utrophin
upregulator SMT C1100 for the treatment of the fatal muscle-wasting
disease Duchenne Muscular Dystrophy (‘DMD’) has
successfully met the endpoints as part of a Phase 1 clinical trial
in healthy volunteers. The trial evaluated a new formulation of SMT
C1100 and the results showed that upon repeat dosing,
concentrations of the drug achieved in the blood plasma, stabilised
at levels that from preclinical studies are expected to
significantly increase utrophin protein production. The new
formulation was also shown to be safe and well-tolerated in this
Phase 1 trial.

SMT C1100 is a potential disease-modifying, oral small-molecule
that works by upregulating (increasing) the amount of a naturally
occurring protein called utrophin tomaintain the healthy function
of muscles. These data strongly support the progression of SMT
C1100 into the next stages of development that includes biomarker
and long-term safety studies, which will be required before a DMD
patient efficacy trial could commence. The latest results will be
presented at the 2012 Action Duchenne Conference, 9-10 November,
London UK.

“Utrophin upregulation is a unique approach for treating DMD
because it could benefit all DMD patients, regardless of their
underlying genetic fault,” commented Glyn Edwards, Chief
Executive Officer of Summit. “We are highly encouraged by
these results, as the new formulation achieves blood concentrations
that have the potential to significantly increase utrophin levels,
with the outcome of maintaining the healthy function of muscles in
patients with DMD. The results therefore strongly support
continuing clinical evaluation of SMT C1100.”

The double blind, placebo-controlled Phase 1 trial examined a new
nanoparticle aqueoussuspension of SMT C1100 in a total of 48
healthy volunteers. The previously reported results from the single
ascending dose cohort showed SMT C1100 to be safe and
well-tolerated at all doses. These new data are being reported from
the repeat dosing cohort where the volunteers received 100mg/kg
twice daily for nine days. These results show that in all
volunteers the blood plasma concentration of SMT C1100 stabilised
after four days of dosing above the required level expected to
increase utrophin protein production by 50% for at least 14 hours a
day in a preclinical model. The plasma levels achieved were
equivalent to those thatgave significant therapeutic benefit in the
gold standard disease model of DMD.

A copy of the presentation being given at the Action Duchenne
conference will be available on Summit’s website after the
event.

The Phase 1 trial has received funding from a group of US DMD
foundations: the MuscularDystrophy Association, Charley’s
Fund, Cure Duchenne, the Foundation to Eradicate Duchenne, Nash
Avery Foundation and Parent Project Muscular Dystrophy.

About SMT C1100 & Utrophin Upregulation
SMT C1100 is designed to upregulate and maintain the production of
utrophin. Utrophin is a protein that is highly expressed in foetal
and regenerating muscle but decreases as the muscle fibre mature
and is eventually replaced by dystrophin, a similar protein that
maintains the integrity and healthy function of muscles. Patients
with DMD are unable to make dystrophin, resulting in muscle fibre
degeneration. However, if utrophin is continually expressed in the
mature fibre, it can functionally replace dystrophin and is
expected to overcome the deficit in patients with DMD. This
approach is expected to be a universal treatment for all DMD
patients regardless of whether the disease was caused by an
inherited or spontaneous mutation. Summit has demonstrated in
non-clinical efficacy studies that SMT C1100 is capable of
switching utrophin production back-on to restore and maintain the
healthy function ofmuscles including the heart and diaphragm. SMT
C1100 has been granted orphan drug status in Europe and the
US.

About Summit
Summit is an Oxford, UK based drugdiscovery and development company
targeting high-value areas of unmet medical need including Duchenne
Muscular Dystrophy and C. difficile infection. Summit is listed on
the AIM market of the London Stock Exchange and trades under the
ticker symbol SUMM. Further information is available at
www.summitplc.com and follow Summit on Twitter (@summitplc).

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